Method of using polymers of amido-sulfonic acid containing monomers and salts as drilling additive

ABSTRACT

A method for producing homopolymers and copolymers from amido-sulfonic acid or salt containing monomers in the presence of high energy mechanical mixing utilizing a final stage polymerization temperature of from about 200° F. to below the degradation temperature of the monomer. The process produces a solid homopolymer or copolymer which can be utilized as fluid loss agents.

This application is a continuation of U.S. application Ser. No.07/402,839, filed Oct. 18, 1989 (now abandoned), which was a division ofU.S. application Ser. No. 07/180,510, filed April 12, 1988 (nowabandoned) which was a division of U.S. application Ser. No. 06/774,269,filed Sept. 10, 1985, (now U.S. Pat. No. 4,812,544). These priorapplications are incorporated herein by reference in their entireties.

BACKGROUND OF THE INVENTION

The present invention relates to a method of utilizing high energymechanical mixing to produce homopolymers and copolymers made fromamido-sulfonic acid monomers or salts thereof. More specifically, thepresent invention relates to producing such polymers by utilizing a highfinal stage polymerization temperature as well as drying the polymerbefore any substantial cooling thereof.

PRIOR ART

U.S. Pat. No. 3,663,518 to Patzelt et al relates to a process forpreparing acrylamide polymers by forming a solution of at least onemonomer and a catalyst, preparing a thin film therefrom, heating saidformed thin film to a temperature sufficient to initiate polymerizationand initiating such polymerization and maintaining the polymerizationtemperature until the polymerization is essentially complete.

U.S. Pat. No. 3,732,193 to Svarz relates to a continuous polymerizationprocess in which an aqueous solution of a water soluble unsaturatedmonomer is polymerized on a heated continuously moving belt to produce adry thin film. The polymer is usually polyacrylamide.

U.S. Pat. No. 3,478,091 to Murfin et al relates to the preparation of2-amido-2-alkenesulfonates by reacting a ketone having at least onehydrogen atom in each alpha position with a nitrile and a sulfuric acid.

U.S. Pat. No. 3,503,941 to Fleetwood relates to the production of dryacrylic polymers produced by polymerizing an aqueous solution of acrylicacid in a pressurized, heated reaction zone and subsequently extrudingthe polymer to yield a fibrous brittle ribbon.

U.S. Pat. No. 3,666,810 to Hoke relates to the preparation ofN-3-aminoalkyl propionamides and to polymers thereof by reactionanalogous N-3-oxohydrocarbon-substituted amides with an amine in thepresence of a reducing agent.

U.S. Pat. No. 4,034,001 to Miller relates to the preparation ofbis-amidoalkanesulfonic acids and salts thereof.

U.S. Pat. No. 4,138,539 to Landolt relates to a multi-step process forpreparing a high molecular weight water soluble synthetic polymer in theform of a readily dissolved powder wherein water soluble ethylenicallyunsaturated monomers and an aqueous redox initiator system are utilized.

U.S. Pat. No. 4,208,329 to Smiley relates to the purification ofacrylonitrile monomer by the removal of oxazole therefrom.

U.S. Pat. No. 4,283,517 to Perricone et al relates to a continuousprocess for solution polymerization of acrylamide by rapidly heating asingle phase high solids aqueous solution of the monomers topolymerization initiation temperature immediately prior to depositing auniform layer thereof, as well as a solution of a polymerizationinitiator, onto a moving surface wherein the surface of the reactionmixture is heated only if necessary to maintain the temperature of thepolymerization from dropping substantially below the polymerizationinitiation temperature.

U.S. Pat. No. 4,293,427 to Lucas et al relates to utilizing a copolymerof an acrylamido alkyl sulfonic acid or alkali metal salt thereof and anacrylamide or N-alkyl acrylamide as an aqueous drilling fluidcomposition.

U.S. Pat. No. 4,309,329 to Lucas et al relates to a terpolymerconsisting essentially of alkali metal acrylate units, hydroxyalkylacrylate units and acrylamide as a filtration control agent in anaqueous drilling fluid.

U.S. Pat. No. 4,404,111 to Bi et al relates to anN,N-dimethylacrylamide/2-acrylamido-2-methyl-propane sulfonic acidcopolymer.

U.S. Pat. No. 4,032,701 to Hughes relates to a continuous method forproducing a dry, solid polyacrylamide by polymerization on a hotrotating disc.

British Patent No. 777,306 relates to a method of polymerizing acrylicacid salts by spraying an aqueous solution of one or more monomersthereof in the presence of an alkali metal or ammonium persulfate onto aheated gaseous medium.

An article relating to "Acrylamide Production Simplified" by Matsuda,Chemtech, May 19, 1977 pages 306-308 sets forth a catalytic hydrationmethod for converting nitriles to amides.

An article relating to "Adiabatic Polymerization of Acrylamide Using aPersulfate-Bisulfite Redox Couple" by Polh et al, Journal of AppliedPolymer Science, Vol 26, pages 611-618 (1980) sets forth the results ofan investigation as to reaction rates under various conditions toestablish the dependence of rate on monomer as well as initiatorconcentration.

SUMMARY OF THE INVENTION

Accordingly, it is an aspect of the present invention to provide amethod for producing a homopolymer from amido-sulfonic acid or saltcontaining monomers. Similarly, another aspect relates to a method forproducing copolymers from amido-sulfonic acid or salt containingmonomers as well as vinyl comonomers containing a nitrogen and/or oxygengroup therein. Solid polymers containing relatively low amounts of watertherein are produced desirably via an aqueous solution in the presenceof high energy mechanical mixing which polymers are desirably subjectedto drying before any substantial cooling thereof.

PREFERRED EMBODIMENTS

The amido-sulfonic acid or salt containing monomers according to thepresent invention can be generally represented by the following formula:##STR1##

wherein R¹ is a hydrocarbyl group having from 1 to 11 carbon atoms. Morespecifically, R¹ is an aliphatic or an olefinic group having from 1 toabout 4 carbon atoms with a vinyl group being preferred. R², R³ R⁴, andR⁵, independently, can be hydrogen or a hydrocarbyl with the provisothat the total number of carbon atoms is 8 or less. Desirably, R² andR³, are hydrogen or a lower alkyl having from 1 to 8 carbon atoms.Preferably, R² and R³ are methyl. Desirably R⁴ and R⁵, independently,are hydrogen or an alkyl having from 1 to 8 carbon atoms with hydrogenbeing preferred. M is H, an ammonium cation, a metal cation, or mixturesthereof. The metal cation can generally be any metal cation anddesirably potassium, magnesium, calcium, lithium, iron, zinc, sodium andthe like. Sodium and potassium are especially preferred. Typically, themonomers are utilized in the form of a salt. A highly desirable monomerfor making either a homopolymer or a copolymer is2-acrylamido-2-methylpropanesulfonic acid or a salt thereof.

The storage of the amido-sulfonic acid or salt containing monomer aswell as polymerization thereof generally occurs in the presence of asolvent. Water is the preferred solvent for the preparation of bothhomopolymers and copolymers of the amido-sulfonic acid or saltcontaining monomers because of the limited solubility of the monomers inmost organic solvents. Other suitable but less desirable solventsinclude dimethylformamide, methanol, dimethylsulfoxide, and other polarsolvents. The amount of the amido-sulfonic acid or salt containingmonomer, or combinations of the various such different monomers in thesolvent generally ranges from about 15% to about 100% by weight basedupon the weight of the monomer and solvent. Generally, an amount isutilized which is less than the saturation weight amount of the monomerin the solvent. With regard to an aqueous solution, the amount ofmonomer is generally from about 40 to 70% by weight, desirably fromabout 40% to about the saturation point of the aqueous solution,preferably from about 50% to about the saturation point of the aqueoussolution, more preferably from about 50% to about 60% and highlypreferable from about 55% to about 60% by weight based upon the weightof said monomer and said aqueous solution. Such high amounts by weightof the monomer are desirable in that the polymerization thereof resultsin higher yields, higher molecular weight, better performance propertiesand is easier to handle.

According to the present invention, a wide variety of copolymers can beprepared utilizing suitable comonomers. Generally, the comonomer is suchthat the overall copolymer is soluble in the solvent and preferablysoluble in water. Oftentimes, the comonomer itself is water soluble. Thevarious comonomers generally contain a vinyl group as well as a nitrogenand/or an oxygen molecule therein. Thus, various acrylamides, variousvinyl pyrrolidones, various vinyl caprolactams, various acrylates,various acrylonitriles, various maleic acids and maleic anhydrides, aswell as various acrylic acids can be utilized. By the term "various" itis meant the different compounds, derivatives or salts thereof known tothe art and to the literature. Considering the acrylamides, specificexamples of monomers include methacrylamide, N,N-dimethylacrylamide,diacetoneacrylamide dimethylaminopropylmethacrylamide,t-butylacrylamide, acrylamide, and the like. Examples of suitablepyrrolidones include N-vinylpyrrolidone and the like. Variouscaprolactams include N-vinylcaprolactam and the like. Suitable acrylatesinclude t-butylacrylate, methylacrylate, dihydrodicyclopentadienylacrylate, 4-butane diol monoacrylate, diethylaminoethylacrylate,methylmethacrylate, and the like. Examples of various acrylonitrilesinclude acrylonitrile, chloroacrylonitrile, methacrylonitrile, and thelike. Besides maleic anhydride or acid, various derivatives and saltsthereof can be utilized. In addition to acrylic acid, variousderivatives thereof can be utilized such as methacrylic acid, and thesalts of these acids. Preferred comonomers of the present inventioninclude N-vinylpyrrolidone, N,N-dimethylacrylamide, diacetoneacrylamide,acrylamide, N-vinylcaprolactam, and t-butylacrylamide withN,N-dimethylacrylamide being highly preferred.

Desirably, the comonomers have good solubility in the solvent. Shouldthe comonomer not have good solubility, it is then desirable to utilizea small portion of another solvent such as an alcohol, for examplemethanol, to render the comonomer soluble in the solvent such as water.The amount of comonomer utilized will generally vary depending upon thetype of comonomer utilized as well as the type of copolymer desired.Generally, it will vary from about 0.1% to about 30% by weight,desirably from about 1% to about 15% and preferably from about 3% toabout 8% by weight based upon the total weight of all of the monomers.

An important aspect of the present invention is the use of high energymechanical mixing the polymerizing monomers regardless of whether ahomopolymer or a copolymer is being made. In other words good mixing isdesired. Various types of high energy mechanical mixing devices includea two roll mill, an extruder, a continuous mixer and the like. It isalso contemplated that static mixers can also be utilized wherein highenergy is imparted by a pump. Inasmuch as the polymerization mixturetends to be viscous and/or tacky, equipment which tends to beself-wiping is desired. Extruders are preferred since the comonomers andother additives can be fed to the feed hopper with a polymerized productbeing produced in a suitable strand, ribbon, or the like. A twin screwextruder is highly desirable in that it is self-cleaning, that is wipesitself free of any residual or viscous polymer.

During polymerization, the various monomers or comonomers are heated toa suitable polymerization temperature. Heating is generally gradualthroughout the heating cycle regardless of the type of high energymechanical mixing device utilized be it a two roll mill, an extruder, orthe like. Should an extruder be utilized, the screw configuration is notimportant and thus generally any type of screw configuration can beutilized. Inasmuch as the polymerization reaction is exothermic, thereaction itself will contribute to the temperature increase. The rate oftemperature increase is generally not critical and the various monomersand additives can be initially added at ambient temperature. Heat isgradually applied until a polymerization temperature is reached. In anextruder, various zones can be heated to produce a suitablepolymerization reaction temperature as well as a final polymerizationreaction temperature. For example, if a three heating zone extruder isutilized, the first zone can be heated to a temperature of approximately90° to 180° F. , the second zone, a temperature of about 150° to about240° F. with the third zone being heated to a temperature of from about200° to approximately 300° F. It is to be understood however that manyother types of heating zones or arrangements via an extrusion reactioncan be utilized.

According to the present invention, it is an important aspect to utilizea high final stage polymerization temperature to facilitate drying ofthe polymer. Otherwise, it has been found that subsequent drying isdifficult and the production of a suitable homopolymer or copolymer isreduced. That a high final stage polymerization temperature could beutilized was unexpected since it was thought that the molecular weightwould be impaired or decreased. A desirable final polymerizationtemperature of a homopolymer or copolymer according to the presentinvention is from about 200° F. to slightly below the degradationtemperature of the lowest degrading monomer, desirably from about 220°F. to just below said degradation temperature, preferably from about230° F. to about 300° F. with a highly preferred temperature being fromabout 240° F. to about 280° F. By the term "slightly below thedegradation temperature", it is meant from about 1° F. to about 20° F.of below said degradation temperature. By the "final polymerizationtemperature" it is meant the temperature at the end of the high energymechanical mixing device which oftentimes is the exit temperature.

According to the present invention, a solid homo- or copolymer isproduced. In addition to conducting the final or terminal polymerizationstep at a high temperature, it is important that the homo- or copolymerbe substantially dried before any substantial reduction in temperatureof the homo- or copolymer occurs. That is, the temperature of the homo-or copolymer should not be reduced to ambient and preferably ismaintained at a temperature of at least 200° F. and more preferably atleast 240° F. before it is subjected to drying. Although the homo- orcopolymer can be maintained or stored at an elevated temperature, it isoften desirable after polymerization to immediately commence dryingthereof. Any conventional or common mode of drying can be utilized suchas irradiation, for example, infrared, convection heat, and the like.Regardless of the high energy mechanical device utilized, inpolymerizing the monomers, the homo- or copolymer is transferred to asuitable vessel to be dried. A desirable mode of drying is the transferof the polymer as from an extruder, to a moving conveyor belt where,because of economic reasons, infrared heat can be utilized to remove thesolvent. The drying temperature at standard conditions is from at leastthe boiling point of the solvent utilized to approximately 600° F. Inthe preferred embodiment wherein water is utilized, the dryingtemperature is from about 212° F. to about 600° F., desirably from about350° F. to about 550° F., and preferably from about 400° F. to about500° F. Drying can also be achieved by applying a vacuum, without heator with heat at temperatures of from ambient to those set forth above.Drying is continued until most of the solvent is removed. Desirably, theamount of solvent such as water remaining in the solid polymer is 20% orless, more desirably 10% or less and preferably 3% by weight or less. Adried product is very desirable because of commercial reasons such asease of size reduction, ease of handling, inventory advantages and thelike.

Generally, the polymerization is carried out in a basic medium whereinvarious polymerization aids can be utilized. Although initiators areoften utilized, polymerization may be conducted without initiators as inthe presence of an inert atmosphere, for example nitrogen. Moreover,polymerization can be carried out in an acidic medium and even withoutheat although heat is desirable. Generally, initiators are utilized inthe aqueous system such as peroxides, persulfates, persulfate-sulfites,various redox systems and the like. Such initiators are well known tothe art and to the literature. A preferred initiator is ammoniumpersulfate.

Another aspect of the present invention relates to utilizing aco-catalyst which is added only initially to the polymerization reactionand not throughout the entire reaction. Such initiators are generallywell known to the art as well as to the literature. An example of such apreferred initiator is sodium meta-bisulfite. Inasmuch as suchinitiators tend to adversely affect the molecular weight of the polymer,they are not utilized in high amounts whenever high molecular weightsare desired. The total amount of the initiator is generally from 0 toabout 5 parts by weight per 100 parts by weight of monomer, desirablyfrom about 0.05 to 0.5 parts and preferably from about 0.2 to about 0.3parts by weight. As noted, the co-catalyst is only added at the onset ofa polymerization process.

Generally, the approximate weight average molecular weight of thehomopolymer or copolymer made according to the present invention willrange from about 100,000 to about 9,000,000, desirably from about500,000 to 6,000,000, and preferably from about 1,000,000 to about3,000,000. Naturally, the molecular weight can be varied depending upondesired end product usage such as those set forth herein below. Once thehomopolymer or copolymer has been produced and dried, it can be groundinto a powder by any conventional grinding apparatus.

Polymers and copolymers produced according to the present invention areuseful in many applications. For example, they can be utilized asdispersants in water to remove, inhibit, or control rust, scale oralluvian deposits, as polymeric surfactants in paints, as polymericscintillators, as polymers for the construction of contact lenses, incosmetics, as anti-fog optical coatings, as fluid thickeners in aqueoushydraulic fluids, and the like. Another desirable use is as a fluid lossagent utilized in oil wells to make an impermeable layer to seal thewall of a drill hole.

The invention will be better understood by reference to the followingexamples.

EXAMPLE 1

A monomer blend consisting of 3.0% weight N,N-dimethylacrylamide, 56.3%(wt) sodium 2-acrylamido-2-methylpropanesulfonate, and 40.7% (wt) waterhaving a pH of 9.0-9.5 is fed to a 4-inch Baker Perkins twin-screwextruder at 70 lb/hr. Just prior to entering the extruder, the monmerfeed is heated to 100°-110° F. An initiator solution consisting of 8.4%(wt) ammonium persulfate and 91.6% (wt) water is fed to the extruder at1.3 lb/hr. Both the monomer solution and the initiator solution are fedto the front of the extruder. At startup, about 1.3 lbs/hour of asolution of 7.1% wt of sodium meta-bisulfite is added and graduallyreduced to zero over a period of 30 minutes. The material temperature ismonitored at 3 different locations in the extruder and at the extruderdie. The material temperatures in the first third, second third, andfinal third of the extruder are 155°-165° F., 210°-220° F., and 225°-235° F. The material temperature at the extruder die is 255°-265° F.Tempered water is fed to jackets on the extruder to maintain thesetemperatures. The residence time in the extruder is 3-5 minutes. Theresulting polymer is extruded in the form of 3/8-inch diameter strandsonto the belt of an infrared conveyor dryer. The polymer moves throughthe dryer at a rate of 1.75-1.85 feet/minute. In the dryer, the polymeris dried to a water content of 1-2% (wt). The polymer reaches atemperature of 450°-500° F. in the dryer. The residence time in thedryer is 8-12 minutes. At the end of the dryer, the polymer falls into acrusher where it is crushed to a suitable size. The copolymer producedis the desired product.

EXAMPLE 2

The procedure from Example 1 is repeated, except that the 8.4% initiatorsolution is fed to the extruder at a rate of 1.75 lb/hr. The materialtemperatures in the extruder and dryer remain as they are in Example 1.The copolymer produced is the desired product.

EXAMPLE 3

The procedure from Example 1 is repeated, except that the 8.4% (wt)initiator solution is fed to the extruder at a rate of 0.75 lb/hr.Except for the material temperature in the first third of the extruder,temperatures in the extruder and the dryer remain as they are inExample 1. The material temperature in the first third of the extruderis 175°-185° F. The copolymer produced is the desired product.

EXAMPLE 4

The procedure from Example 1 is repeated, except that a monomer blendconsisting of 2.6% (wt) N,N-dimethylacrylamide, 48.7% (wt) sodium2-acrylamido-2-methylpropanesulfonate, and 48.7% (wt) water is fed tothe extruder at 80.9 lb/hr. The initiator solution concentration andfeed rate are maintained as indicated in Example 1. The materialtemperatures in the first third, second third, and final third of theextruder are 140°-150° F., 200°-210° F., and 220°-230° F. The materialtemperature at the extruder die is 250°-260° F. In the dryer, thepolymer is dried to a water content of 1-2% (wt). The copolymer producedis the desired product.

EXAMPLE 5

The procedure from Example 1 is repeated, except that a monomer solutionconsisting of 58% (wt) sodium 2-acrylamido-2-methylpropanesulfonate and42% (wt) water is fed to the extruder at 70 lb/hr. An initiator solutionconsisting of 8.4% (wt) ammonium persulfate and 91.6% (wt) water is fedto the extruder at 0.8 lb/hr. The material temperature in the firstthird, second third, and final third of the extruder are 135°-145° F.,200°-210° F., and 200°-210° F. The material temperature at the extuderdie is 200°-210° F. The resulting polymer is dried to a water content of0-1% (wt). The final dried homopolymer has a weight-average molecularweight of 900,000.

While in accordance with the present invention, a best mode of preferredembodiment has been illustrated in detail, the invention is not limitedthereto, but rather by the scope of the attached Claims.

What is claimed is:
 1. A process, comprising:adding to a drill hole atleast one homopolymer prepared by the process comprising the steps: (i)adding at least one amido-sulfonic acid or salt containing monomer to areactor, said amido-sulfonic acid or salt containing monomer having theformula: ##STR2## wherein: R¹ is a hydrocarbyl group having from 1 toabout 11 carbon atoms; R², R³, R⁴ and R⁵ are, independently, hydrogen orhydrocarbyl groups, provided that the total number of carbon atoms inR², R³, R⁴, and R⁵ and 8 carbon atoms or less; and M is hydrogen,ammonium, metal cation or mixture thereof: (ii) polymerizing saidamido-sulfonic acid or salt containing monomer using high energymechanical mixing, the final stage of step (ii) being conducted at atemperature of from about 200° F. to below the degradation temperatureof said monomer.
 2. The process of claim 1 wherein R¹ is an aliphaticgroup.
 3. The process of claim 1 wherein R¹ is an olefinic group.
 4. Theprocess of claim 1 wherein R¹ is a vinyl group.
 5. The process of claim1 wherein R¹ has from 1 to about 4 carbon atoms.
 6. The process of claim1 wherein R², R³, R⁴ and R⁵ are, independently, hydrogen or alkyl groupsof 1 to about 8 carbon atoms.
 7. The process of claim 1 wherein M isselected from the group consisting of potassium, magnesium, calcium,lithium, iron, zinc, sodium or a mixture of two or more thereof.
 8. Theprocess of claim 1 wherein said monomer is 2-acrylamido-2-methylpropanesulfonic acid or a salt thereof.
 9. The process of claim 1 wherein saidmonomer is dispersed in at least one solvent.
 10. The process of claim 1wherein said monomer is dispersed in water.
 11. The process of claim 1wherein said monomer is dispersed in dimethylformamide, methanol ordimethylsulfide.
 12. The process of claim 1 wherein said monomer isdispersed in at least one solvent, the concentration of said monomer insaid solvent ranging from about 15% to about 100% by weight based on thecombined weight of said monomer and said solvent.
 13. The process ofclaim 1 wherein said monomer is dispersed in at least one solvent, theconcentration of said monomer in said solvent being less that thesaturation weight of amount of said monomer in said solvent.
 14. Theprocess of claim 1 wherein said monomer is dispersed in at least onesolvent, the concentration of said monomer in said solvent ranging fromabout 40% to about 70% by weight based on the combined weight of saidmonomer and said solvent.
 15. The process of claim 1 wherein saidmonomer is dispersed in at least one solvent, the concentration of saidmonomer in said solvent ranging from about 50% to about 60% by weightbased on the combined weight of said monomer and said solvent.
 16. Theprocess of claim 1 wherein said monomer is dispersed in at least onesolvent, the concentration of said monomer in said solvent ranging fromabout 55% to about 60% by weight based on the combined weight of saidmonomer and said solvent.
 17. The process of claim 1 wherein step (ii)is conducted in a two-roll mill, extruder, continuous mixer or staticmixer.
 18. The process of claim 1 wherein step (ii) is conducted in anextruder.
 19. The process of claim 1 wherein step (ii) is conducted in atwin-screw extruder.
 20. The process of claim 1 wherein step (ii) isconducted in an extruder having three heating zones, the first zoneoperating at a temperature in the range of about 90° F. to about 180°F., the second zone operating at a temperature in the range of about150° F. to about 240° F., the third zone operating at a temperature inthe range of about 200° F. to about 300° F.
 21. The process of claim 1wherein the final stage of step (ii) is conducted at a temperature inthe range of about 220° F. to slightly below the degradation temperatureof said monomer.
 22. The process of claim 1 wherein the final stage ofstep (ii) is conducted at a temperature in the range of about 230° F. toabout 300° F.
 23. The process of claim 1 wherein the final stage of step(ii) is conducted at a temperature in the range of about 240° F. toabout 280° F.
 24. The process of claim 1 wherein said polymer issubstantially dried before any substantial reduction in temperature ofsaid polymer occurs.
 25. The process of claim 1 wherein said polymer isdried, said polymer being maintained at a temperature of at least about200° F. prior to being dried.
 26. The process of claim 1 wherein saidmonomer is dispersed in at least one solvent, and said polymer is driedat a temperature in the range of the boiling point of said solvent up toabout 600° F.
 27. The process of claim 1 wherein said polymer is driedin a vacuum.
 28. The process of claim 1 wherein said polymer is dried ata temperature in the range of about 212° F. to about 600° F.
 29. Theprocess of claim 1 wherein said polymer is dried at a temperature in therange of about 350° F. to about 550° F.
 30. The process of claim 1wherein said polymer is dried at a temperature in the range of about400° F. to about 500° F.
 31. The process of claim 1 wherein said polymeris dried sufficiently so that the amount of solvent remaining in saidpolymer is less than about 20% by weight.
 32. The process of claim 1wherein the polymerization of said monomer is conducted in the presenceof at least one initiator.
 33. The process of claim 1 wherein thepolymerization of said monomer is conducted in the presence of aperoxide, persulfate, persulfate-sulfite or redox system.
 34. Theprocess of claim 1 wherein the polymerization of said monomer isconducted in the presence of ammonium persulfate.
 35. The process ofclaim 1 wherein the polymerization of said monomer is conducted in thepresence of a co-catalyst, said co-catalyst being added at the beginningof the polymerization reaction.
 36. The process of claim 1 wherein thepolymerization of said monomer is conducted in the presence of sodiummeta-bisulfite, said sodium meta-bisulfite being added at the beginningof the polymerization reaction.
 37. The process of claim 1 wherein saidpolymer has a weight average molecular weight in the range of about100,000 to about 9,000,000.
 38. The process of claim 1 wherein saidpolymer has a weight average molecular weight in the range of about500,000 to about 6,000,000.
 39. The process of claim 1 wherein saidpolymer has a weight average molecular weight in the range of about1,000,000 to about 3,000,000.
 40. The process of claim 1 wherein saidpolymer is ground into a powder.
 41. A process comprising:adding to adrill hole at least one amido-sulfonic acid or salt containingcopolymer, said copolymer being prepared by the process comprising thesteps of; (i) adding an amido-sulfonic acid or salt containing monomerand at least one copolymerizable comonomer to a reactor, saidamido-sulfonic acid or salt containing monomer having the formula##STR3## wherein: R¹ is a hydrocarbyl group having from 1 to about 11carbon atoms; R², R³, R⁴, and R⁵ are, independently, hydrogen orhydrocarbyl groups with the proviso that the total number of carbonatoms in R², R³, R⁴, and R⁵ is 8 carbon atoms or less; M is hydrogen,ammonium, metal cation or mixture thereof; the amount of saidcopolymerizable comonomer being from about 0.1% to about 30% by weightbased upon the total weight of said amido-sulfonic acid or saltcontaining monomer and said copolymerizable comonomer; and (ii)polymerizing said amido-sulfonic acid or salt containing monomer andsaid copolymerizable comonomer using high energy mechanical mixing toprovide said copolymer.
 42. The process of claim 41 wherein the finalstage of step (ii) is conducted at a temperature of from about 200° F.to below the degradation temperature of said monomer or said comonomer.43. The process of claim 41 wherein R¹ is an aliphatic group.
 44. Theprocess of claim 41 wherein R¹ is an olefinic group.
 45. The process ofclaim 41 wherein R¹ is a vinyl group.
 46. The process of claim 41wherein R¹ has from 1 to about 4 carbon atoms.
 47. The process of claim41 wherein R², R³, R⁴ and R⁵ are, independently, hydrogen or alkylgroups of 1 to about 8 carbon atoms.
 48. The process of claim 41 whereinm is selected from the group consisting of potassium, magnesium,calcium, lithium, iron, zinc, sodium or a mixture of two or morethereof.
 49. The process of claim 41 wherein said monomer is2-acrylamido-2-methylpropane sulfonic acid or a salt thereof.
 50. Theprocess of claim 41 wherein said comonomer contains a vinyl group and atleast one nitrogen and/or oxygen atom.
 51. The process of claim 41wherein said comonomer is at least one acrylamide, vinyl pyrrolidone,vinyl caprolactam, acrylate, acrylonitrile, acrylic acid, maleic acid,maleic anhydride, or salt thereof.
 52. The process of claim 41 whereinsaid comonomer is methacrylamide, N,N-dimethylacrylamide,diacetoneacrylamide, dimethylaminopropylmethacrylamide,t-butylacrylamide, acrylamide or a mixture of two or more thereof. 53.The process of claim 41 wherein said comonomer is N-vinylpyrrolidone,N-vinylcaprolactam, or a mixture thereof.
 54. The process of claim 41wherein said comonomer is t-butylacrylate, methylacrylate,dihydrodicylopentadienyl, acrylate, 4-butane diol monoacrylate,diethylaminoethylacrylate, methylmethacrylate, acrylonitrile,chloroacrylonitrile, methacrylonitrile, or a mixture of two or morethereof.
 55. The process of claim 44 wherein said comonomer is N,N-dimethylacrylamide.
 56. The process of claim 41 wherein said monomerand said comonomer are dispersed in at least one solvent.
 57. Theprocess of claim 41 wherein said monomer and said comonomer aredispersed in water.
 58. The process of claim 41 wherein said monomer andsaid comonomer are dispersed in dimethylformamide, methanol ordimethylsulfide.
 59. The process of claim 41 wherein said monomer andsaid comonomer are dispersed in at least one solvent, the combinedconcentration of said monomer and said comonomer in said solvent rangingfrom about 15% to about 100% by weight based on the combined weight ofsaid monomer, comonomer and solvent.
 60. The process of claim 41 whereinsaid monomer and comonomer are dispersed in at least one solvent, thecombined concentration of said monomer and comonomer in said solventbeing less than the saturation weight of amount of said monomer andcomonomer in said solvent.
 61. The process of claim 41 wherein saidmonomer and comonomer are dispersed in at least one solvent, thecombined concentration of said monomer and comonomer in said solventranging from about 40% to about 70% by weight based on the combinedweight of said monomer, comonomer and solvent.
 62. The process of claim41 wherein said monomer and comonomer are dispersed in at least onesolvent, the combined concentration of said monomer and comonomer insaid solvent ranging from about 50% to about 60% by weight based on thecombined weight of said monomer, comonomer and solvent.
 63. The processof claim 41 wherein said monomer and comonomer are dispersed in at leastone solvent, the combined concentration of said monomer and comonomer insaid solvent ranging from about 55% to about 60% by weight based on thecombined weight of said monomer, comonomer and solvent.
 64. The processof claim 41 wherein step (ii) is conducted in a two-roll mill, extruder,continuous mixer or static mixer.
 65. The process of claim 41 whereinstep (ii) is conducted in an extruder.
 66. The process of claim 41wherein step (ii) is conducted in a twin-screw extruder.
 67. The processof claim 41 wherein step (ii) is conducted in an extruder having threeheating zones, the first zone operating at a temperature in the range ofabout 90° F. to about 180° F., the second zone operating at atemperature in the range of about 150° F., to about 240° F., the thirdzone operating at a temperature in the range of about 200° F. to about300° F.
 68. The process of claim 41 wherein the final stage of step (ii)is conducted at a temperature in the range of about 220° F. to slightlybelow the degradation temperature of said monomer or said comonomer. 69.The process of claim 41 wherein the final stage of step (ii) isconducted at a temperature in the range of about 230° F. to about 300°F.
 70. The process of claim 41 wherein the final stage of step (ii) isconducted at a temperature in the range of about 240° F. to about 280°F.
 71. The process of claim 41 wherein said copolymer is substantiallydried before any substantial reduction in temperature of said copolymeroccurs.
 72. The process of claim 41 wherein said copolymer is dried,said copolymer being maintained at a temperature of at least about 200°F. prior to being dried.
 73. The process of claim 41 wherein saidmonomer and comonomer are dispersed in at least one solvent, and saidcopolymer is dried at a temperature in the range of the boiling point ofsaid solvent up to about 600° F.
 74. The process of claim 41 whereinsaid copolymer is dried in a vacuum.
 75. The process of claim 41 whereinsaid copolymer is dried at a temperature in the range of about 212° F.to about 600° F.
 76. The process of claim 41 wherein said copolymer isdried at a temperature in the range of about 350° F. to about 550° F.77. The process of claim 41 wherein said copolymer is dried at atemperature in the range of about 400° F. to about 500° F.
 78. Theprocess of claim 41 wherein said copolymer is dried sufficiently so thatthe amount of solvent remaining in said copolymer is less than about 20%by weight.
 79. The process of claim 41 wherein the polymerization ofsaid monomer and comonomer is conducted in the presence of at least oneinitiator.
 80. The process of claim 41 wherein the polymerization ofsaid monomer and comonomer is conducted in the presence of a peroxide,persulfate, persulfate-sulfite or redox system.
 81. The process of claim41 wherein the polymerization of said monomer and comonomer is conductedin the presence of ammonium persulfate.
 82. The process of claim 41wherein the polymerization of said monomer and comonomer is conducted inthe presence of a co-catalyst, said co-catalyst being added at thebeginning of the polymerization reaction.
 83. The process of claim 41wherein the polymerization of said monomer and comonomer is conducted inthe presence of sodium meta-bisulfite, said sodium meta-bisulfite beingadded at the beginning of the polymerization reaction.
 84. The processof claim 41 wherein said copolymer has a weight average molecular weightin the range of about 100,000 to about 9,000,000.
 85. The process ofclaim 41 wherein said copolymer has a weight average molecular weight inthe range of about 500,000 to about 6,000,000.
 86. The process of claim41 wherein said copolymer has a weight average molecular weight in therange of about 1,000,000 to about 3,000,000.
 87. The process of claim 41wherein said copolymer is ground into a powder.